Lately, the electronic devices having the contact detection unit such as a touch sensor as a member for detecting an input operation by a user have been increasingly used for mobile terminals such as mobile phones. As a method used by a contact detection unit to detect the input operation, there are known variety of types, such as a resistive film type, a capacitive type, an optical type and the like. Those types detect a contact by a user's finger, a stylus pen and the like.
As the electronic device having the contact detection unit, a touch panel having the contact detection unit and a display unit laminated to each other has been known. In the touch panel, the display unit is disposed on a rear face of the contact detection unit and displays graphical images of operation keys and buttons (hereinafter, referred to as input objects). When the user presses the input object displayed on the display unit, the contact detection unit detects a contact at a pushed position. A technique to provide a tactile sensation to the user in response to pressing at a predetermined pressure load or higher has also been known.
Japanese Patent Laid-Open No. 2006-39745 discloses a touch panel type input apparatus which allows a multiple level selection by pressing operations.
Incidentally, when a plurality of input objects are arranged on the display unit, the user may inadvertently select an input object adjacent to a desired input object. In this case, an undesired operation starts and, if an important operation being performed is cancelled by the undesired operation, the important operation may not be recovered. Moreover, the user needs to perform an additional operation to cancel the undesired operation.